Blood feeding & flea allergy dermatitis (Sponsored by Lilly)

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Mar 01, 2008
By dvm360.com staff

All fleas biteā€”fast


Highlights
For years, veterinary dermatologists have stated that only a single flea bite is necessary to produce the clinical signs of flea allergy dermatitis (FAD) in hypersensitive animals. Most flea-control products kill fleas fast enough to interfere with most egg production, which breaks the flea life cycle. However, they're not able to prevent fleas from biting and feeding before they are killed.


Flea feeding findings
Fleas almost immediately begin to feed once they find a host.1 One study found that 25% to 60% of fleas fed within five minutes, and another found that 89% fed within five minutes.2,3 Fleas are voracious feeders, and females can consume up to 15 times their body weight in blood in one day.

The speed with which a product kills fleas and prevents them from injecting antigen may influence how quickly the irritation from the inflammatory response to flea bites improves. Studies have demonstrated that neither topical nor systemic insecticides can stop initial biting and feeding.4-6 But in one study, systemically active insecticides decreased blood feeding more rapidly and more profoundly than topically active insecticides.6 To sum up, a fast residual speed of kill is an important element in a successful flea-control product.

As new compounds are developed, research on blood feeding, residual speed of kill, and the relative effects on FAD will need to be conducted. This data can provide insight into their potential effectiveness in controlling flea bites and managing FAD.

References

1. Dryden M. Gaafar S. Blood consumption by the cat flea, Ctenocephalides felis felis (Siphonaptera: Pulicidae). J Med Entemol 1991;28:394-400.

2. Cadiergues MC, Hourcq P, Cantaloube B, et al. First bloodmeal of Ctenocephalides felis felis (Siphonaptera: Pulicidae) on cats: Time to initiation and duration of feeding. J Med Entemol 2000;37:634-636.

3. McCoy CM, Dryden MW, Broce AB. Blood feeding dynamics of cat fleas in flea feeding chambers attached to cats, in Proceedings. Am Assoc Vet Parasitol, 2003:32.

4. Dryden MW. Laboratory evaluations of topical flea control products, in Proceedings. British Vet Dermatol Study Group 1998:14-17.

5. Franc M, Cadiergues MC. Antifeeding effect of several insecticidal formulations against Ctenocephalides felis on cats. Parasite 1998;5:83-86.

6. McCoy CM. Blood feeding dynamics of newly emerged cat fleas, Ctenocephalides felis (Bouche) (Siphonaptera: Pulicidae) in chambers attached to insecticide-treated and untreated cats. MS thesis. Kansas State University 2006:44.